Re: [syzbot] [kernel?] WARNING: kobject bug in goku_remove

[syzbot <syzbot+06ec7624018233e17113@syzkaller.appspotmail.com>]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
WARNING: proc registration bug in goku_probe

goku_udc 0000:00:1d.7: version: 30-Oct 2003 (dma IN)
goku_udc 0000:00:1d.7: irq 19, pci mem ffffc9000363f000
------------[ cut here ]------------
proc_dir_entry 'driver/udc' already registered
WARNING: fs/proc/generic.c:404 at proc_register+0x5db/0x910 fs/proc/generic.c:404, CPU#2: syz-executor259/6021
Modules linked in:
CPU: 2 UID: 0 PID: 6021 Comm: syz-executor259 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:proc_register+0x5e7/0x910 fs/proc/generic.c:404
Code: 00 00 00 fc ff df 48 89 f9 48 c1 e9 03 80 3c 01 00 0f 85 50 02 00 00 48 8d 3d 25 49 6b 0e 48 8b 44 24 10 48 8b b0 d0 00 00 00 <67> 48 0f b9 3a 48 c7 c7 00 78 ea 8e e8 98 0a 01 09 48 8b 4c 24 30
RSP: 0018:ffffc90003087698 EFLAGS: 00010246
RAX: ffff88801daebb80 RBX: 0000000000000000 RCX: 1ffff11003b5d78a
RDX: ffff88803e408e9c RSI: ffff88801daebc5c RDI: ffffffff91281ed0
RBP: ffff88801daebc30 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff88803e408dc0
R13: dffffc0000000000 R14: ffff88803e409af8 R15: ffffed1007c811d3
FS:  0000555580895400(0000) GS:ffff8880d5fe9000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f40537909c0 CR3: 00000000567ce000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 proc_create_single_data+0xd9/0x130 fs/proc/generic.c:681
 goku_probe.cold+0x328/0x524 drivers/usb/gadget/udc/goku_udc.c:1822
 local_pci_probe+0xdd/0x1b0 drivers/pci/pci-driver.c:332
 pci_call_probe+0x176/0x800 drivers/pci/pci-driver.c:394
 __pci_device_probe drivers/pci/pci-driver.c:455 [inline]
 pci_device_probe+0x1cd/0x370 drivers/pci/pci-driver.c:489
 call_driver_probe drivers/base/dd.c:628 [inline]
 really_probe+0x241/0xa60 drivers/base/dd.c:706
 __driver_probe_device+0x20e/0x450 drivers/base/dd.c:868
 driver_probe_device+0x4a/0x140 drivers/base/dd.c:898
 __driver_attach+0x21f/0x5b0 drivers/base/dd.c:1292
 bus_for_each_dev+0x13e/0x1d0 drivers/base/bus.c:383
 pci_add_dynid+0x2b5/0x370 drivers/pci/pci-driver.c:77
 new_id_store+0x2a9/0x5b0 drivers/pci/pci-driver.c:249
 drv_attr_store+0x74/0xb0 drivers/base/bus.c:125
 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:145
 kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:345
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x6ac/0x1050 fs/read_write.c:687
 ksys_write+0x12a/0x250 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7eff25b5de37
Code: 48 89 fa 4c 89 df e8 98 1d 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007fff3195caa0 EFLAGS: 00000202 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000555580895400 RCX: 00007eff25b5de37
RDX: 000000000000000d RSI: 00007fff3195cb60 RDI: 0000000000000003
RBP: 00007fff3195d7e0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000003
R13: 00007fff3195ce00 R14: 00007fff3195cbe0 R15: 0000000000000001
 </TASK>
----------------
Code disassembly (best guess):
   0:	00 00                	add    %al,(%rax)
   2:	00 fc                	add    %bh,%ah
   4:	ff                   	lcall  (bad)
   5:	df 48 89             	fisttps -0x77(%rax)
   8:	f9                   	stc
   9:	48 c1 e9 03          	shr    $0x3,%rcx
   d:	80 3c 01 00          	cmpb   $0x0,(%rcx,%rax,1)
  11:	0f 85 50 02 00 00    	jne    0x267
  17:	48 8d 3d 25 49 6b 0e 	lea    0xe6b4925(%rip),%rdi        # 0xe6b4943
  1e:	48 8b 44 24 10       	mov    0x10(%rsp),%rax
  23:	48 8b b0 d0 00 00 00 	mov    0xd0(%rax),%rsi
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	48 c7 c7 00 78 ea 8e 	mov    $0xffffffff8eea7800,%rdi
  36:	e8 98 0a 01 09       	call   0x9010ad3
  3b:	48 8b 4c 24 30       	mov    0x30(%rsp),%rcx


Tested on:

commit:         3aa1dcaa Revert "wifi: mt76: Disable napi when removin..
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=155cf979580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=c44651ea7dd2f307
dashboard link: https://syzkaller.appspot.com/bug?extid=06ec7624018233e17113
compiler:       gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
patch:          https://syzkaller.appspot.com/x/patch.diff?x=12acf979580000